As a generic mode of address, “commander” was appropriate to many military officers. Almost anyone in command of a distinct ship, outfit or taskforce could be called "commander" of the unit. Examples of these commanders were found within all military branches. They ranged from Fleet Commanders, Field Commanders, and Flight Commanders to more prestige full titles such as Force Commanders and High Commanders. It must be noted though, that the commanding officers of naval capital ships usually preferred to be addressed as "Captain". According to Emperor Palpatine in the Imperial Handbook: A Commander's Guide, the official field manual for officers within the Imperial Military, a commander within the Empire was required to excel, which requires that they fight and if need be die in the service